Goniometric device for determining the dip and strike of strata from bore-core



Jan. 9, 1940. F. HUMPHREYS 2,186,677

GONIOMETRIC DEVICE FOR DETERMINING THE DIP AND STRIKE 0F STRATA FROM BORE-CORE Original Filed June 3, 1936 Patented Jan. 9, 1940 I UNITED STATES PATENT 'OFFICE Go IoME'riuc DEVICE FOR. DETERMINING THE mr AND STRIKE F STRATA FROM BORE-CORE Frank Humphrey's, Klerksdorp, Union of South Africa Original application June 3, 1936, Serial No. 83,387. Divided and this application May 14, 1937, Serial No. 142,934. In the Union of South Africa September 12, 1935 '8 Claims. (Cl. 33-1) The present invention relates to goniometric until it occupies a position which corresponds devices fordetermining the dip and strike of in all respects with that which it occupied when strata existing underground. The dip of a strain situ in the bore-hole. It is convenient to make turn is the angle between the plane of the stratum it substantially parallel to the position it ocand a horizontal plane, whilst the strike of the cupied when in situ in the bore-hole. 5

stratum is the angle which a vertical plane pass- The complete Series Of Operations y be 511111- ing through the intersection of the plane of the marized in somewhat more detail as follows. A stratum and a horizontal plane makes with a bore-hole is drilled to the desired depth, the survertical plane passing through the magnetic face at the bottom of the bore-hole is ground north. until it is a flatplane perpenditular to the axis 10 In order to ascertain the dip and strike of of the lower end .of the bore-hole, and all acstrata existing underground it is first of all necescumulated sand or silt is then removed from the sary to sink a bore-hole to intersect the stratum bottom of the bore-hole by any suitable flushing to be investigated and to extract a piece of boredevice. The bore-hole surveyi instrument is hole from the lower end of the bore-hole. A borelowered to the bottom of a bore-hole and a mark 15 hole of any considerable depth, however, always is made on the flat surface at the bottom of the deviates from its original vertical direction so bore-hole by means of a resiliently yielding finger that readings taken from the piece of bore-core which is caused to scratch a line on said surface when mounted in a vertical position will not by slightly raising and l w rin th stru correctly represent the dip and strike of the se- After an interval determinedby a ng de- 20 lected stratum. To interpret the bore-core cor v ce insi the instrument, a photographic rectly it is necessary to obtain a record of the 0rd is made of the position of the devices in the inclination and magnetic bearing of the lower instrument indicating the inclination and magend of the bore-hole at the depth of the senetic bearing of the bore-hole. The bore-hole lected stratum. The inclination of the bore-hole surveying instrument is then removed and drill- 25 is the angle which the axis of the bore-hole at ing of the bore-hole is continued so as to form the depth in question makes with a vertical line a stump of core carrying the marked surface, in the vertical plane containing said axis, and the and said stump is broken 01f d extracted Om magnetic bearing of the bore-hole is the angle the hole. It is then mounted in a goniometric which the vertical plane through the axis of the device provided with adjustments whereby, by 80 bore-hole at the depth in question makes with .making use of the photographic record, the borea vertical plane passing through the magnetic core may be set in a position which corresponds north. in all respects with the position that it originally An object of the present invention is to prooccupied when in situ in the bore-hole. The dip 5 vide a goniometrlc device for receiving the seand strike of any selected stratum i vthe piece 85 lected portion of bore-core and for setting itto of bore-core may then be read 05 y further a position which corresponds in all respects with devices on the goniometric devicethat which it occupied when in situ in the bore- A description w now be v y W Of hole. example, of a goniometric device according to the 40 Apparatus for use in obtaining data for setting invention, reference being made to the accom- 40' the bore-core has been described in parent appanying drawing comprising Figures I and II. plication Serial No. 83,387 filed June 3, 1936, and Figure I shows a photographic record for use comprises a bore-hole surveying instrument in operating a goniometric device according to which is lowered to the bottom of a bore-hole the invention.

when the bore-hole has reached the depth at Figur II h ws a eoni m ri device a cor in 45 which it is to be surveyed. The bore-hole surto the invention. Veying instrument is then actuated to mark the It will be assumed that a piece of bore-core bore-core at the lower end of the bore-hole and to provided with a scratch mark at its upper end record certain data which can be subsequently has been obtained in the manner described in employed for obtaining the inclination and magthe parent application Serial No. 83,387 filed 50 netic bearing of the lower end of the bore-hole June 3, 1936, and that the inclination and magand the magnetic bearing of the mark on the netic bearing of the lower end of the bore-hole bore-core. When the bore-core has been mounthave been recorded in the form of the photoed in the goniometric device its position can be graphic'record of Figure I. In Figure I, 30 is adjusted in accordance with these three angles the image of a deflection scale and.29' is the 55 image of a pointer at the end of a pendulum moving over the scale; 3| is the image of a compass card and 33' is the image of the compass needle. The angle indicated by the pointer image 29 is the angle of inclination of the borehole, the angle between the centre line of the scale image 30' and the needle image 33' is the magnetic bearing of the bore-hole, and the angle indicated by the needle image 33' is the magnetic bearing of the scratch mark on the surface at the bottom of the bore-hole. Thus in the example shown, the inclination of the bore-hole is about 22, the magnetic bearing of the borehole is about east of north and the magnetic bearing of the scratch mark is about 240 east of north, i. e., .west of north. The piece of bore-core 39 is clamped in a holder 40 with its scratched end 39' uppermost. The elliptical line 65 indicates the trace on the cylindrical surface of the core 39, of the plane of the surface of contact between two strata, one atleast of which is the stratum which is being surveyed. The

holder 49 is attached to a horizontal spindle 42 mounted in an upright standard 43 so as to be rotatable about its own axis. The standard 43 is secured to one end of a horizontal base 44 which is free to rotate about the centre of a circular graduated scale 45 and may be clamped in any desired position therein by means of a thumbscrew 46. The scale 45 is marked on a plane baseboard 41 provided with levels 48 and levelling screws 49.

In order to facilitate the use of the goniometric device it is advisable to set the baseboard 4! so that the zero mark on the scale 45 points approximately to the magnetic north. The baseboard is then levelled by the levelling screws 49.

When the baseboard has been thus levelled, the holder 40 is rotated about its axis until a pointer 59 fixed to the horizontal spindle 42 and moving over the graduated arc 5| indicates that the bore-core 39 has the same inclination that it had when in the earth. The holder is then clamped by tightening the thumbscrew 52. The horizontal arm 44 is then moved aroundthe scale 45 until a cutback edge 44' which is radial to the centre of the scale 45 is against the degree mark corresponding to the magnetic bearing of the bore-hole.

The top of the standard 43 is made hollow to receive an extension piece 53 which is free to rotate about the vertical axis of the standard 43 and to be clamped in any desired position by the thumb-screw 54. The top of the extension piece 53 is provided with a vertical slot 55 arranged to receive one end of a bar 56 which is pivoted to the extension piece 53 by a horizontal pivot 53' and is thus free to rotate in a vertical plane and to be held in any desired position by a tight frictional coupling with the slot 55.

A further bar 51 is pivoted to the other end of the bar 56 in a friction-tight manner by a horizontal pivot 51' so as to turn in a vertical plane and has pivoted at its other end a triangularshaped plate 58 which is capable of being clamped to bar 51 by the thumb-screw 63 and has attached to it a transparent plate or visor 59 provided with a line 60 running along its centre at right angles to the plane of movement of the bar 56. The transparent plate 59 is attached at right angles to the plate 58. A pendulum pointer 6| hangs freely from a hub 64 in front of a degrees scale 62 which is rigidly secured to the plate 58 and is so graduated that when the plate 59 is in a horizontal plane the pendulum 6| incides with the angle on baseboard scale 45 cor responding to the magnetic bearing of the scratch mark as obtained from the photographic record of Figure I.

Thumb-screw 54 is now clamped; and by ad- Justing the position of 56, 51 and 58, the visor 59 is brought immediately above the clamped piece of core 39. Viewing down through line 60 or the parallel edge of the visor 59, the core 39 is then rotated in the holder 40 (the position of the holder remaining unchanged) until the line 69 or the parallel edge of the visor 59 coincides with the mark 4| on the upper flat surface of the core 39. The core 39 is now in a position which corresponds in all respects with that which it occupied when in situ in the bore-hole and is substantially parallel thereto.

The upper or lower face of the visor 59 is now brought into the plane of the selected stratum in the core, as that plane is revealed by its trace 65 on the periphery of the core. The movement of the visor 59 to bring it to this position comprises'the following movement components in any combination which is necessary, viz., rotation of the assembly 53, 56, 51 and 59 about the axis of the vertical standard 43; angular movement of arm 56 in a vertical plane about its pivot 53; angular movement of arm 51 in a vertical plane about its pivot 51; and angular movement of the visor 59 about its axis of rotation with respect to the arm 51, i. e., the axis of the thumb screw 63. The visor 59 then has the same dip and strike as the selected stratum. The dip of the stratum is then read off from the position of the pendulum pointer 61 with respect to scale 62 whilst the strike of the stratum is read off from the angle indicated on the scale 45 when so viewed through thevisor 59 that the engraved line 69 passes through the centre of the scale 45.

I claim:

1. A goniometric device provided with a holder for receiving a piece of bore-core, a device for indicating the inclination of the axis of said holder, means for rotating said holder in a vertical plane until the axis of the holder assumes a desired inclination, a device for indicating the magnetic bearing of the axis of said holder,

means for rotating saidholder until its axis assumes a desired magnetic bearing, and directionally indicative means arranged to be set to a desired magnetic bearing.

2. A goniometric. device provided with a holder for receiving a piece of bore-core, a device for indicating the inclination of the axis of said holder, means for rotating said holder in a vertical plane until the axis of the holder assumes a desired inclination, a device for indicating the magnetic bearing of theaxis of said holder, means for rotating said holder until its axis assumes a desired magnetic bearing, a visor arranged to be set in any desired plane, and means for reading oil? the dip and strike of the plane occupied by said visor.

3. A goniometric device provided with a holder for receiving a piece of bore-core,,means for rotating said holder in a vertical plane, a vertical standard to which said holder is attached, a horizontal base carrying said standard and rotatable in a horizontal plane, an arm attached to said standard, and a visor pivotally attached to said arm and movable in a direction parallel to any plane passing through the vertical standard and said arm. g

4. A goniometric device provided with a holder for receiving a piece oi-bore-core, a device for indicating the inclination of the axis oi said holder, means for rotating said holder in a vertical plane until the axis oi said holder assumes through the vertical standard and said arm.

5. A goniometric device provided with a holder for receiving a piece of bore-core, means including graduated scales for adjusting the position oi said holder to a position in which the axis of the holder has a desired inclination and magnetic bearing, and directionally indicative means of said holder to a position in which the axis of the holder which coincides with the axes of pieces of bore-core when inserted therein, has a desired inclination and magnetic bearing, avisor arranged to be set to any desired plane, and means for reading of! the angle which said visor makes with a horizontal plane and the angle which a vertical plane passing through the intersection of said visor and a horizontal plane makes with avertical plane passing through the magnetic north.

7. A goniometric device provided with a holder for receiving a piece of bore-core, means including graduated scales for adjusting the position oi said holder to a position. in which the axis of the holder has a desired inclination and magnetic bearing, directionally indicativemeans arranged to be set to a desired magnetic bearing with the aid of one of said scales, and means for guiding of said holder to a position-in which the .axis

of the holder has a desired inclination and magnetic bearing, an additional graduated scale, a. visor associated with said additional graduated scale, and means for indicating on said additional graduated scale the angle which the plane of the visor makes with the horizontal plane;

\ FRANK HUMPHREYS. 

